Question: Do you know how magnets work and why they don't work on some metals?

Edward Hughes answered on 23 Jun 2014:

Great question – I always wondered about this at school!

It comes down to the electrons around the nucleus of an atom. Whenever any charged particle moves it creates a magnetic field. Each electron is moving and spinning, and so acts like a miniature magnet.

Most of the time the electrons arrange themselves so that these magnetic effects cancel out. This explains why most materials aren’t attracted to magnets. But in a few metals (like iron) the electron structure is just right to leave an overall effect! This means that you can get an overall magnetic field for the atom.

Most of the time random jiggling of the electrons still means this effect will disappear. But when you bring a magnet close to a piece of iron the electrons line up because of electromagnetic interactions. This makes your piece of iron into a magnet itself. Stroking your piece of iron with a magnet can make it permanently magnetic!

The way the electrons spin is quite interesting. They can spin in the normal way, like a spinning top. But they can also spin another way that we can’t visualize. This is because the world is described by quantum mechanics and special relativity! These two powerful and counter-intuitive ideas mean that electrons can have an intrinsic quantum spin of +1/2 or -1/2 even when they aren’t spinning like a top.

Btw there’s more details on reddit here (http://tinyurl.com/62wxgkw).